Crystallized silicon-containing material with hierarchical and organized porosity

Abstract

Material with hierarchical and organized porosity in the microporosity and mesoporosity domains, consisting of at least two elementary spherical particles, each one of said particles comprising a matrix based on silicon oxide, mesostructured, having a mesopore diameter ranging between 1.5 and 30 nm and exhibiting microporous and crystallized walls of thickness ranging between 1 and 60 nm, said elementary spherical particles having a maximum diameter of 200 microns. The preparation of said material is also described.

The invention claimed is: 
     
       1. A material with hierarchical and organized porosity in the microporosity and mesoporosity domains said material comprising at least two elementary spherical particles, each one of said particles comprising a matrix based on silicon oxide, mesostructured, having a mesopore diameter ranging between 1.5 and 30 nm and exhibiting microporous and crystallized walls consisting of zeolitie entities of a thickness ranging between 1 and 60 nm, said elementary spherical particles having a maximum diameter of 200 microns. 
     
     
       2. A material as claimed in  claim 1 , such that the mesopore diameter ranges between 2 and 20 nm. 
     
     
       3. A material as claimed in  claim 1 , such that said zeolitic entities comprise at least one zeolite selected from a group consisting of MFI, BEA, FAU and LTA. 
     
     
       4. A material as claimed in  claim 1 , such that said matrix based on silicon oxide is entirely silicic. 
     
     
       5. A material as claimed in  claim 1 , such that said matrix based on silicon oxide comprises at least one element X that is aluminum, iron, boron, indium or gallium. 
     
     
       6. A material as claimed in  claim 5 , such that element X is aluminium. 
     
     
       7. A material as claimed in  claim 1 , such that said mesostructured matrix has a hexagonal, cubic or vermicular structure. 
     
     
       8. A material as claimed in  claim 1 , such that said elementary spherical particles have a diameter ranging between 50 nm and 3 microns. 
     
     
       9. A material according to  claim 8 , having a mesoporous volume between 0.01 and 1 ml/g and a microporous volume ranging between 0.01 and 0.4 ml/g, both volumes being measured by nitrogen volumetric analysis and wherein the specific surface of the elementary spherical particles being between 250 and 1000 m 2 /g. 
     
     
       10. A material as claimed in  claim 1 , such that the material has a specific surface area ranging between 100 and 1100 m 2 /g. 
     
     
       11. A method of preparing a material as claimed in  claim 1 , comprising the following stages: a) preparing a clear solution containing the zeolitic entity precursor elements, i.e. at least one structuring agent, at least one silicic precursor and optionally at least one precursor of at least one element X selected from among aluminium, iron, boron, indium and gallium ; b) mixing into a solution at least one surfactant and at least said clear solution obtained in stage a) such that the ratio of the volumes of inorganic and organic matter V inorganic /V organic  ranges between 0.26 and 4; c) aerosol atomizing said solution obtained in stage b) so as to lead to the formation of spherical droplets; d) drying said droplets; e) autoclaving the particles obtained in stage d); f) drying said particles obtained in stage e); and g) eliminating said structuring agent and said surfactant so as to obtain a crystallized material with hierarchical and organized porosity in the microporosity and mesoporosity domains. 
     
     
       12. A preparation method as claimed in  claim 11 , such that the ratio of the inorganic and organic matter volumes ranges between 0.3 and 2. 
     
     
       13. A preparation method as claimed in  claim 11 , such that element X is aluminium. 
     
     
       14. A preparation method as claimed in  claim 11 , such that said surfactant is a three-block copolymer, each block consisting of a poly(alkylene oxide) chain. 
     
     
       15. A preparation method as claimed in  claim 14 , such that said three-block copolymer consists of two poly(ethylene oxide) chains and of one poly(propylene oxide)chain. 
     
     
       16. A method of preparing a material as claimed in  claim 1 , comprising the following stages: a′) preparing, from at least one structuring agent, at least one silicic precursor and optionally at least one precursor of at least one element X selected from among aluminium, iron, boron, indium and gallium, a solution containing zeolite nanocrystals of maximum nanometric size equal to 60 nm in order to obtain a colloidal solution wherein said nanocrystals are dispersed ; b′) mixing into a solution at least one surfactant and at least said solution obtained in stage a′) such that the ratio of the volumes of inorganic and organic matter V inorganic /V organic  ranges between 0.26 and 4; c′) aerosol atomizing said solution obtained in stage b′) so as to lead to the formation of spherical droplets; d′) drying said droplets; and g′) eliminating said structuring agent and said surfactant so as to obtain a crystallized material with hierarchical and organized porosity in the microporosity and mesoporosity domains. 
     
     
       17. A method as claimed in  claim 16 , such that said stage d′) is followed by a stage e′) comprising autoclaving the particles obtained in stage d′), then by a stage f′) comprising drying said particles obtained in stage e′), said stage f′) being then followed by said stage g′). 
     
     
       18. A method as claimed in  claim 16 , such that stage b′) is carried out by mixing into a solution at least one surfactant, at least said colloidal solution obtained in stage a′) and at least one clear solution containing the zeolitic entity precursor elements, i.e. at least one structuring agent, at least one silicic precursor and possibly at least one precursor of at least one element X selected from among aluminium, iron, boron, indium and gallium. 
     
     
       19. A method of preparing a material as claimed in  claim 1 , comprising the following stages: a″) redispersing into a solution zeolite crystals so as to obtain a colloidal solution of zeolite nanocrystals of maximum nanometric size equal to 60 nm, b″) mixing into a solution at least one surfactant, at least said colloidal solution obtained in a″) and at least one clear solution containing the zeolitic entity precursor elements, i.e. at least one structuring agent, at least one silicic precursor and optionally at least one precursor of at least one element X selected from among aluminium, iron, boron, indium and gallium, said mixture being such that the ratio of the volumes of inorganic and organic matter V inorganic /V organic  ranges between 0.26 and 4; c″) aerosol atomizing said solution obtained in stage b″) so as to lead to the formation of spherical droplets; d″) drying said droplets; e″) autoclaving the particles obtained in d″); f″) drying said particles obtained in e″), and g″) eliminating said structuring agent and said surfactant so as to obtain a crystallized material with hierarchical and organized porosity in the microporosity and mesoporosity domains.